I'm very private about my possessions. I hate people touching my stuff, I hate people using my things, and I hate having things examined. Its the point where, even if we were dating, you aren't allowed to use my phone unless you really need to make a call or its an emergency. That, and I have the view that the TSA is a tremendous violation of my rights against unwarranted searches of my persons and property, and the opposite of what our justice system is founded on here in the United States. Innocent is the default assumption, but when you walk through the TSA checkpoint you are assumed to be guilty until they find nothing on you. Also I have a deep mistrust of people in uniform who aren't in the military or who aren't cops telling me to walk through checkpoints with my shoes off and everything I have with me in a bin to be scanned. Its too much the feeling of being a number, and while I'm able to accept a great deal of dehumanization, something about that is just a tad beyond the line I've drawn.
I can get most of that, except the phone thing. Is there any rational reason why you wouldn't want somebody to use your phone? This doesn't qualify as a "fear", but I have a strong aversion to wearing someone else's shoes. I think it's disgusting.